Maori groups trying to block the sale of state assets until their water rights issues are resolved have opened their submissions at the High Court in Wellington.

Helen Cull QC acting for the Pouakani Claims Trust indicated her submission would take most of the day before the Maori Council began its submission.

Cull argued that before the assets are transferred from being a state-owned enterprise to the mixed ownership model assets should be "tagged or marked" or some other mechanism used to preserve Maori interests in water.

Justice Ronald Young said he did not understand why the Government needed to act now before the transfer because water rights were determined under the Resource Management Act which the Government could change anytime.

Justice Young said there were ways of providing commercial redress.

However the claimants, which include the Waikato River Dam Trust which Cull also represents, may have a stronger point over cultural issues such as access that are not necessarily commercial.

But he said the Waitangi Tribunal did not argue that in its findings on stage one of its inquiry.

Cull said the tribunal had parked those issues for stage two of its inquiry.

Justice Young said the Crown's "king hit" submission was that ministers were carrying out Parliament's intent by transferring the state assets to the mixed ownership model.

That would mean the decision to transfer the assets out of the State-Owned Enterprises Act, implemented by an order in council, was not reviewable by the court.

But Cull said Orders-in-Council could be reviewable as was the original law that enabled the transfer.

The case is set down for four days but is expected to wrap up on Wednesday or early Thursday.

The Government has put on hold the sale of 49 per cent of Mighty River Power until the judicial review is resolved.